Insulin and Zinc — Two Peas in a Pancreas
Zinc plays a very important role in your body’s production, storage, and use of insulin, the hormone that lowers high blood glucose levels. And, zinc is crucial to your immune system, it enhances your senses of smell and taste, is involved in the metabolism of the macronutrients, promotes tissue growth and cell reproduction, is an antioxidant working to protect cells from damage, and is involved with hundreds of enzymes.
Zinc in pancreatic beta cells binds to several insulin molecules, six to be exact, forming what’s called an insulin hexamer for storage. In fact, long acting insulin formulations for injection — NPH or Lantus, to name two — contain zinc so that the insulin is bound in hexamers that convert to the active insulin monomer (a single insulin molecule) slowly.
Several studies have shown that high blood glucose levels increase the excretion of zinc in urine, and zinc deficiency seems to promote insulin resistance. A study in Finland found that heart disease fatalities and heart attacks in a study group of people with diabetes were more likely in the subjects with lower blood zinc levels.
Recent research shows that zinc manages the behavior of amylin, a protein also secreted by pancreatic beta cells to help slow carbohydrate absorption. Unmanaged amylin, according to research published in the Journal of Molecular Biology, can form clumps that interfere with insulin secretion in type 2 diabetes (where insulin is still produced by the pancreas).
There is not sufficient evidence to suggest getting more than the recommended dietary allowance of zinc brings additional benefits to blood glucose management, and excess zinc can cause imbalances with copper and other micronutrients.
It seems prudent, however, to include foods or a multivitamin that puts adequate zinc into your diet. The current RDA is 8 mg/d for adult women and 11 mg/d for adult men — the RDA varies for children, adolescents, and pregnant or nursing women.
Foods that contain zinc include oysters (the richest source), crab, beef, beans, yogurt, cheese, oatmeal, and almonds. The absorption of zinc from many plant sources is inhibited by phylates, which are also present in the grain, so the bioavailability may be less than zinc from animal sources.